This invention pertains to an apparatus for holding an intraocular lens for inserting an intraocular lens into the eye.
Various diseases of the human eye may require removal of the eye's natural lens. For example, one of these diseases causes the natural lens to become opaque, thus blocking the light before it hits the retina. This effect is commonly referred to as a cataract.
After the lens has been removed, an artificial lens must be provided to restore the patient's vision. Generally there are three methods of providing such a lens: regular glasses, external contact lens and intraocular lens.
Regular glasses used for cataracts are very thick and therefore found aesthetically objectionable by many patients. Contact lenses are inappropriate to some patients, especially older ones who do not have the dexterity necessary for inserting or removing the lens. Thus, for many patients the intraocular lenses present the best alternative.
Depending on their actual position within the eye, intraocular lenses are categorized either as anterior chamber lenses or posterior chamber lenses. As the name implies an anterior chamber lens is installed in the anterior chamber between the iris and the ocular jelly. Sometimes, this lens is positioned in the plane of the iris. In order to insure that the lens does not shift, the lens is sometimes sutured or otherwise affixed to the iris. Anterior chamber lenses are the predominant and safer type of lenses, and of course they must be used after intracapsular surgery, during which the capsular bag is removed.
Posterior chamber lenses can be used after extracapsular surgery, i.e., when the cataract is removed but the capsular bag is left in place. Although posterior chamber lenses may be positioned between the bag and the iris, it was found that it is safer to install these lenses within the capsular bag itself.
Intraocular lenses have gone through an evolution of their own. While the initial lenses had bulky, complicated appendages for securing the lens within the eye, the latest lenses have much simpler mechanisms. One of the most common type of intraocular lens have a number a flexible loops or haptics. In the relaxed position these loops are coplanar with the lens and engage the side walls of the eye in a spring action thus holding the lens in place. The loops are made of polypropylene or other similar material and lenses are available with loops of a variety of sizes, shapes, and colors.
It is well known that eye surgery is a very delicate procedure. Any inadvertant move on the part of the surgeon may further damage the eye. This is especially true for the process of implanting an intraocular eye because the lens itself is very small and, further, it must be precisely positioned so that it can focus the light entering the eye onto the retina. The lenses with loops are especially difficult to install because the loops in their open position cover an area which is much larger than the actual area of the lens. Various devices have been made which assist the surgeon in this procedure, however most of them are too bulky and expensive.
One device which has been used in particular with lenses having loops is the so-called SHEET GLIDE. This device is simply a flat flexible plastic strip which is slightly narrower than the diameter of the lens. In order to use this device, the surgeon makes an appropriate incision in the eye, and then he slips the SHEET GLIDE into the eye with its tip positioned in the general location to be occupied by the lens. Next, he slides the lens on the glide into the eye. The incision in the eye must be large enough to accomodate the loops, and the SHEET GLIDE does not provide any protection of the eye during the implantation.